Researchers discover oldest pollinators entombed in amber

Studying amber obtained from Cretaceous-era deposits, an international team of paleontologists have discovered the oldest known insects engaged in pollination. The 105-million to 110-million-year-old thrips they found are coated in pollen grains that were presumably used to feed the insects’ offspring.

Thysanopterans, commonly called thrips, are tiny, slender insects with fringed wings -- hence the name, from the Greek thysanos (fringed) and pteron (wing). Thrips are generally considered pests because they eat plant tissues, but some are efficient pollinators for several species of flowering plants.

Amber samples containing the insects were obtained from a site in the Basque-Cantabrian Basin of northern Spain, a team headed by paleontologist Enrique Penalver of the Instituto Geologico y Minero de Espana in Madrid, reported in the Proceedings of the National Academy of Sciences. They imaged the insects using the synchrotron at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The images revealed two new species of thrips, which they named Gymnospollisthrips major and G. minor.

The thrips had hundreds of pollen grains stuck to their bodies. The exterior of the insects had highly specialized hairs with a ringed structure to increase their ability to collect pollen grains, very similar to those of contemporary pollinators like bees.

The small pollen grains are believed to come from a cycad or ginkgo tree. Ginkgos are either male or female, and males produce pollen that must be transported to the female tree by wind or insects. The researchers speculated that the thrips established colonies in the female trees and carried pollen from the male trees to feed their offspring. “Thrips might turn out to be one of the first pollinator groups in geological history,” said paleontologist Carmen Soriano of ESRF.

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